<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        /* 
            1 运算符 = 运算符号 + 运算单元
            2 运算一定有一个返回值 `1+2=3`

            typeof运算规则
            1 语法：`typeof 变量` 或者 `typeof 值`
            2 计算返回值为当前的变量或者值的数据类型（字符串等8大类型）
        */
        const a = 100;
        const b = "hello";
        const c = true;
        const d = undefined;
        const e = 100n;
        const f = {};
        const g = Symbol();//S 需要大写
        const h = null;

        console.log(typeof 100);//number
        console.log(typeof "hello");//string
        console.log(typeof true);//boolean
        console.log(typeof undefined);//undefined
        console.log(typeof 100n);//bigint
        console.log(typeof {});//object
        console.log(typeof Symbol());//symbol
        console.log(typeof null);//object ✖ null ✔ 官方承认的错误
    </script>
</body>

</html>